We quantitatively analyze the role of financial frictions and resource misallocation in explaining development dynamics. Our model economy with financial frictions converges to the new steady state slowly after a reform triggers efficient reallocation of resources; the transition speed is half that of the conventional neoclassical model. Furthermore, in the model economy, investment rates and total factor productivity are initially low and increase over time. We present data from the so-called miracle economies on the evolution of macro aggregates, factor reallocation, and establishment size distribution that support the aggregate and micro-level implications of our theory.

This paper analyzes the role of specialized high-skilled labor in the growth of the service sector as a share of the total economy. Empirically, we emphasize that the growth has been driven by the consumption of services. Rather than being driven by low-skill jobs, the importance of skill-intensive services has risen, and this has coincided with a period of rising relative wages and quantities of high-skilled labor. We develop a theory where demand shifts toward ever more skill-intensive output as income rises, and because skills are highly specialized this lowers the importance of home production relative to market services. The theory is also consistent with a rising level of skill and skill premium, a rising relative price of services that is linked to this skill premium, and rich product cycles between home and market, all of which are observed in the data.

What is the aggregate and distributional impact of microfinance? To answer this question, we develop a quantitative macroeconomic framework of entrepreneurship and financial frictions in which microfinance is modelled as guaranteed small-size loans. We discipline and validate our model using recent empirical evaluations of small-scale microfinance programs. We find that the long-run general equilibrium impact is substantially different from the short-run effect. In the short-run partial equilibrium, output and capital increase with microfinance but total factor productivity (TFP) falls. In the long run, when general equilibrium effects are considered, as should be for economy-wide microfinance interventions, scaling up microfinance has only a small impact on per-capita income, because an increase in TFP is offset by lower capital accumulation. However, the vast majority of the population benefits from microfinance directly and indirectly. The welfare gains are larger for the poor and the marginal entrepreneurs, although higher interest rates in general equilibrium tilt the gains toward the rich.

Macroeconomic development remains an important policy goal because of its ability to lift entire populations out of poverty. In our review of the literature, we emphasize that the best way to achieve this objective is to embrace a synthesis of methods and ideas, with the science of experiments as a unifying feature. Randomized controlled trials need representative data and structural modeling, and macro models need to be designed and disciplined to the realities and data of developing-country economies. Macroeconomic models have key lessons for gathering and analyzing micro evidence and for moving to an evaluation of macro policy. Resource constraints, heterogeneity, general equilibrium effects, obstacles to trade, dynamics, and returns to scale can all play key roles. A synthesis for macro development is well under way.

We provide a simple quantitative general equilibrium model of occupational choice with credit market frictions to analyze the aggregate and distributional effects of asset transfer programs. Asset transfer programs have a positive but transient effect on aggregate productivity, and a negative impact on the aggregate capital stock. On net they have a negative but small effect on per capita income. The effects are very heterogeneous across treated individuals. We compare the results in our model to those from recent randomized control trials and historical natural experiments.

We develop a quantitative framework to explain the relationship between aggregate/sector-level total factor productivity (TFP) and financial development across countries. Financial frictions distort the allocation of capital and entrepreneurial talent across production units, adversely affecting measured productivity. In our model, sectors with larger scales of operation (e.g., manufacturing) have more financing needs, and are hence disproportionately vulnerable to financial frictions. Our quantitative analysis shows that financial frictions account for a substantial part of the observed cross-country differences in output per worker, aggregate TFP, sector-level relative productivity, and capital-to-output ratios.

We provide a tractable, quantitatively‐oriented theory of innovation and technology diffusion to explore the role of international trade in the process of development. We model innovation and diffusion as a process involving the combination of new ideas with insights from other industries or countries. We provide conditions under which each country's equilibrium frontier of knowledge converges to a Fréchet distribution, and derive a system of differential equations describing the evolution of the scale parameters of these distributions, that is, countries' stocks of knowledge. The model remains tractable with many asymmetric countries and generates a rich set of predictions about how the level and composition of trade affect countries' frontiers of knowledge. We use the framework to quantify the contribution of bilateral trade costs to long‐run changes in TFP and individual post‐war growth miracles. For our preferred calibration, we find that both gains from trade and the fraction of variation of TFP growth accounted for by changes in trade more than double relative to a model without diffusion.

We study the evolution of market-oriented policies over time and across countries. We consider a model in which own and neighbors' past experiences influence policy choices through their effect on policymakers' beliefs. We estimate the model using a large panel of countries and find that it fits a large fraction of the policy choices observed in the postwar data, including the slow adoption of liberal policies. Our model also predicts that there would be reversals to state intervention if nowadays the world was hit by a shock of the size of the Great Depression.

Using a broad panel of advanced economies, we document that increases in GDP per capita are associated with a systematic shift in the composition of value added to sectors that are intensive in high-skill labour, a process we label as skill-biased structural change. It follows that further development in these economies leads to an increase in the relative demand for skilled labour. We develop a quantitative two-sector model of this process as a laboratory to assess the sources of the rise of the skill premium in the U.S. and a set of ten other advanced economies, over the period 1977 to 2005. For the U.S., we find that the sector-specific skill neutral component of technical change accounts for 18–24% of the overall increase of the skill premium due to technical change, and that the mechanism through which this component of technical change affects the skill premium is via skill-biased structural change.